.page-about {
  background: var(--ink);
  color: var(--white);
  padding-bottom: 72px;
}

.page-about .breadcrumbs {
  padding-top: 22px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--mist);
  display: flex;
  gap: 8px;
  align-items: center;
}

.page-about .breadcrumbs a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.page-about .breadcrumbs a:hover {
  color: var(--volt);
  border-bottom-color: var(--volt);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 22px 0 46px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  z-index: 0;
  top: -170px;
  right: -160px;
  width: 420px;
  height: 420px;
  background: radial-gradient(circle at center, rgba(198, 255, 61, .18), rgba(198, 255, 61, 0) 68%);
  transform: rotate(-6deg);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 6px;
  height: 3px;
  background: linear-gradient(90deg, var(--volt), rgba(198, 255, 61, 0) 58%, var(--flame));
  opacity: .55;
  transform: skewX(-18deg);
  pointer-events: none;
}

.page-about .hero-inner {
  position: relative;
  z-index: 1;
}

.page-about .hero-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  color: var(--volt);
}

.page-about .hero-title {
  margin: 0;
  font-size: clamp(28px, 7.2vw, 54px);
  line-height: 1.16;
  font-weight: 800;
  letter-spacing: -.02em;
  max-width: 22ch;
}

.page-about .hero-lead {
  margin: 20px 0 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ice);
}

.page-about .hero-facts {
  list-style: none;
  margin: 26px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 12px;
}

.page-about .fact-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 24px;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--volt);
}

.page-about .fact-label {
  display: block;
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--mist);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  align-items: start;
}

.page-about .about-rail {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  padding: 14px 14px 16px;
}

.page-about .rail-eyebrow {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--mist);
}

.page-about .rail-list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
  position: relative;
}

.page-about .rail-item {
  flex: 0 0 auto;
}

.page-about .rail-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ice);
  text-decoration: none;
  font-size: 13px;
  line-height: 1.4;
  white-space: nowrap;
  transition: border-color .22s var(--ease-out), color .22s var(--ease-out), background .22s var(--ease-out);
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--mist);
  letter-spacing: .06em;
}

.page-about .rail-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--line);
  flex: 0 0 auto;
  transition: background .22s var(--ease-out), box-shadow .22s var(--ease-out);
}

.page-about .rail-link:hover {
  border-color: var(--volt-deep);
  color: var(--volt);
}

.page-about .rail-link.is-current {
  background: rgba(198, 255, 61, .12);
  border-color: var(--volt);
  color: var(--volt);
}

.page-about .rail-link.is-current .rail-num {
  color: var(--volt);
}

.page-about .rail-link.is-current .rail-dot {
  background: var(--volt);
  box-shadow: 0 0 0 4px rgba(198, 255, 61, .16);
  animation: about-pulse 2.4s ease-in-out infinite;
}

.page-about .rail-foot {
  display: none;
  margin: 16px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  line-height: 1.8;
  color: var(--mist);
}

@keyframes about-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .55; }
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding: 28px 0 8px;
  border-top: 1px solid var(--line);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 4px;
}

.page-about .section-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .section-num {
  font-family: var(--font-mono);
  font-size: 36px;
  line-height: .92;
  letter-spacing: -.05em;
  color: var(--volt);
  opacity: .8;
  flex: 0 0 auto;
}

.page-about .section-title {
  margin: 0;
  font-size: clamp(21px, 4.6vw, 30px);
  line-height: 1.28;
  font-weight: 800;
  letter-spacing: -.01em;
}

.page-about .prose {
  margin: 0 0 16px;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--ice);
}

.page-about .prose a {
  color: var(--volt);
  text-decoration: none;
  border-bottom: 1px dashed rgba(198, 255, 61, .5);
}

.page-about .prose a:hover {
  color: var(--volt-deep);
  border-bottom-style: solid;
}

/* ---------- 三条做法 ---------- */
.page-about .principles-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .principle-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .principle {
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--volt-deep);
  border-radius: var(--radius-m);
  padding: 16px 18px;
}

.page-about .principle-index {
  display: inline-block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--volt);
  border: 1px solid rgba(198, 255, 61, .45);
  border-radius: 999px;
  padding: 2px 10px;
}

.page-about .principle-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
}

.page-about .principle p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  overflow: hidden;
  background: var(--panel);
  box-shadow: var(--shadow-panel);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-figure--square img {
  aspect-ratio: 1 / 1;
}

.page-about .about-figure--wide img {
  aspect-ratio: 16 / 9;
}

.page-about .about-figure figcaption {
  padding: 10px 14px 12px;
  font-size: 12px;
  line-height: 1.8;
  color: var(--mist);
  border-top: 1px solid var(--line);
}

.page-about .principles-wrap .about-figure {
  margin-bottom: 0;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-top: 18px;
}

.page-about .team-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  padding: 16px 18px;
}

.page-about .team-card--lead {
  background: linear-gradient(150deg, rgba(198, 255, 61, .1), var(--panel) 62%);
  border-color: var(--volt-deep);
}

.page-about .team-card--wide {
  background: var(--pitch);
  border-color: var(--line);
}

.page-about .team-stat {
  display: block;
  font-family: var(--font-mono);
  font-size: 32px;
  line-height: 1.05;
  letter-spacing: -.03em;
  color: var(--volt);
}

.page-about .team-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--volt);
  border: 1px solid rgba(198, 255, 61, .45);
  border-radius: 999px;
  padding: 2px 10px;
}

.page-about .team-role {
  margin: 8px 0 8px;
  font-size: 16px;
  font-weight: 800;
}

.page-about .team-card p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .team-card p a {
  color: var(--volt);
  text-decoration: none;
  border-bottom: 1px dashed rgba(198, 255, 61, .5);
}

.page-about .team-card--wide p {
  margin-top: 10px;
  color: var(--ice);
}

/* ---------- 版本 ---------- */
.page-about .version-list {
  display: grid;
  gap: 10px;
  margin-top: 6px;
}

.page-about .version {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  overflow: hidden;
  transition: border-color .24s var(--ease-out);
}

.page-about .version:hover,
.page-about .version[open] {
  border-color: var(--volt-deep);
}

.page-about .version summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
}

.page-about .version summary::-webkit-details-marker {
  display: none;
}

.page-about .version[open] summary {
  border-bottom: 1px solid var(--line);
  background: rgba(198, 255, 61, .07);
}

.page-about .version-tag {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--ink);
  background: var(--volt);
  border-radius: 999px;
  padding: 3px 10px;
  flex: 0 0 auto;
}

.page-about .version-name {
  flex: 1 1 auto;
  min-width: 0;
}

.page-about .version-hint {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--mist);
  position: relative;
  padding-right: 18px;
}

.page-about .version-hint::after {
  content: "+";
  position: absolute;
  right: 0;
  top: -2px;
  font-size: 16px;
  line-height: 1;
  color: var(--volt);
  transition: transform .24s var(--ease-out);
}

.page-about .version[open] .version-hint::after {
  transform: rotate(45deg);
}

.page-about .version-body {
  padding: 14px 16px 18px;
}

.page-about .version-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.9;
  color: var(--ice);
}

/* ---------- 纸质引文 ---------- */
.page-about .paper-note {
  margin: 20px 0 0;
  background: var(--paper);
  color: #1b2333;
  border-radius: var(--radius-l);
  padding: 20px 20px 16px;
  transform: rotate(-.5deg);
  box-shadow: var(--shadow-panel);
  border-left: 4px solid var(--flame);
}

.page-about .paper-quote {
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  font-weight: 600;
}

.page-about .paper-cite {
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: #5c6479;
}

/* ---------- 合作技能树 ---------- */
.page-about .tree {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 18px 0 20px;
}

.page-about .tree-root {
  border: 1px solid var(--volt-deep);
  border-radius: var(--radius-m);
  background: linear-gradient(150deg, rgba(198, 255, 61, .16), var(--panel) 72%);
  padding: 16px 18px;
}

.page-about .tree-root-label {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--volt);
}

.page-about .tree-root-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--ice);
}

.page-about .tree-branches {
  list-style: none;
  margin: 0;
  padding: 0 0 0 20px;
  position: relative;
  display: grid;
  gap: 10px;
}

.page-about .tree-branches::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  bottom: 26px;
  width: 1px;
  background: repeating-linear-gradient(180deg, var(--line) 0 6px, transparent 6px 12px);
}

.page-about .branch {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  padding: 14px 16px;
  transition: border-color .24s var(--ease-out), transform .24s var(--ease-out);
}

.page-about .branch::before {
  content: "";
  position: absolute;
  left: -15px;
  top: 24px;
  width: 15px;
  height: 1px;
  background: var(--line);
  transform-origin: left center;
  transform: scaleX(.5);
  transition: transform .28s var(--ease-out), background .24s var(--ease-out);
}

.page-about .branch-dot {
  position: absolute;
  left: -19px;
  top: 20px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--line);
  transition: background .24s var(--ease-out), box-shadow .24s var(--ease-out);
}

.page-about .branch:hover {
  border-color: var(--volt);
  transform: translateX(2px);
}

.page-about .branch:hover::before {
  transform: scaleX(1);
  background: var(--volt);
}

.page-about .branch:hover .branch-dot {
  background: var(--volt);
  box-shadow: 0 0 0 4px rgba(198, 255, 61, .16);
}

.page-about .branch-title {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: -.01em;
}

.page-about .branch p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  margin-top: 26px;
  padding: 22px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  background: linear-gradient(120deg, var(--panel), var(--ink) 78%);
  display: grid;
  gap: 14px;
}

.page-about .cta-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--white);
  font-weight: 600;
}

.page-about .cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 桌面 ---------- */
@media (min-width: 720px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .principles-wrap {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: stretch;
  }

  .page-about .team-card--lead {
    grid-column: 1 / span 2;
    grid-row: 1 / span 2;
  }

  .page-about .team-card--wide {
    grid-column: 1 / -1;
  }

  .page-about .tree {
    grid-template-columns: minmax(0, .82fr) minmax(0, 1.6fr);
    align-items: start;
    gap: 22px;
  }

  .page-about .tree-root {
    position: sticky;
    top: 96px;
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    padding: 24px 26px;
  }
}

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: 236px minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 92px;
    padding: 18px 18px 20px;
  }

  .page-about .rail-list {
    flex-direction: column;
    overflow: visible;
    padding-left: 0;
    gap: 2px;
  }

  .page-about .rail-list::before {
    content: "";
    position: absolute;
    left: 12px;
    top: 10px;
    bottom: 10px;
    width: 1px;
    background: repeating-linear-gradient(180deg, var(--line) 0 6px, transparent 6px 12px);
  }

  .page-about .rail-item {
    position: relative;
  }

  .page-about .rail-link {
    border: 0;
    border-radius: var(--radius-s);
    padding: 9px 10px 9px 28px;
    white-space: normal;
    background: transparent;
    width: 100%;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 2px 8px;
  }

  .page-about .rail-dot {
    position: absolute;
    left: 8px;
    top: 14px;
    width: 9px;
    height: 9px;
  }

  .page-about .rail-link.is-current {
    background: rgba(198, 255, 61, .1);
    border-radius: var(--radius-s);
  }

  .page-about .rail-text {
    flex: 1 1 100%;
    font-size: 13.5px;
  }

  .page-about .rail-foot {
    display: block;
  }

  .page-about .section-num {
    font-size: 46px;
    min-width: 62px;
  }

  .page-about .about-section {
    padding-top: 34px;
  }

  .page-about .prose {
    font-size: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-link.is-current .rail-dot {
    animation: none;
  }

  .page-about .branch,
  .page-about .branch::before,
  .page-about .rail-link {
    transition: none;
  }

  .page-about .branch:hover {
    transform: none;
  }
}